Every page of a room's messages (opening the room, scrolling back, the
refresh after reconnecting, the bot API) selects WHERE room_id = ? ORDER BY
created_at LIMIT 40. With only the room_id index, SQLite reads every
message in the room and sorts them in a temporary B-tree to return 40, so
these requests grow with the room's history.
A composite index on (room_id, created_at) lets SQLite read the 40 rows in
order straight from the index. It covers every lookup the room_id index
served, so that one goes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NuTtwJKhb77Dv7EQqv2C3C
Previously we had to use structure.sql since schema.rb didn't have support for virtual tables that we needed for search. Since Campfire's release virtuals tables have been added to Rails, so there is no need to use structure.sql anymore
Marcello Costagliola
Mike Dalessio
Stanko K.R.